EP0433468A1 - Strom-Spannungswandler - Google Patents
Strom-Spannungswandler Download PDFInfo
- Publication number
- EP0433468A1 EP0433468A1 EP89123358A EP89123358A EP0433468A1 EP 0433468 A1 EP0433468 A1 EP 0433468A1 EP 89123358 A EP89123358 A EP 89123358A EP 89123358 A EP89123358 A EP 89123358A EP 0433468 A1 EP0433468 A1 EP 0433468A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- amplifier
- voltage converter
- input terminal
- current voltage
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
- H04B10/693—Arrangements for optimizing the preamplifier in the receiver
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
- H03F3/08—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light
- H03F3/082—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light with FET's
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
- H03F3/08—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light
- H03F3/087—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light with IC amplifier blocks
Definitions
- the invention relates to a current voltage converter comprising: an input terminal, amplifier means comprising an inverting amplifier, the amplifier having an inverting input terminal and an output terminal, the output terminal being coupled to the input terminal of the current voltage converter via a resistor.
- optical time-domain reflectometers used for example for testing glass fibers
- an optical receiver having an avalanche photodiode or a PIN diode as receiving element for an optical signal and a transimpedance amplifier which converts the photocurrent delivered by the receiving diode into a voltage.
- the principle of such a circuit is described in Hewlett-Packard Journal, December 1988, pages 26 to 28.
- the present invention shows a possibility to provide a transimpedance amplifier or more generally a current voltage converter with a better behavior on overloading without changing the bandwidth and other essential parameters of the amplifier.
- the invention is characterized in that a voltage clipping means is connected between the input terminal of the current voltage converter and a fixed potential, that the inverting amplifier has a gain such that the maximum output voltage of a specific polarity of the inverting amplifier is the product of the gain between the input terminal of the current voltage converter and the output terminal of the inverting amplifier by the corresponding maximum voltage across the clipping means.
- the maximum output voltage is chosen such that the inverting amplifier is not saturated.
- the gain is much smaller than the open-loop gain of an operational amplifier which is normally used for the inverting amplifier, and because of the low gain a relatively high input voltage occurs which can readily be limited or clipped by the clipping means.
- the clipping voltage or threshold of the clipping means is the above mentioned maximum voltage across the clipping means.
- the invention is characterized in that one end of a voltage clipping means is connected with the input terminal of the current voltage converter, that the inverting amplifier has a gain such that the maximum of the output voltage of a specific polarity of the inverting amplifier is the product of the gain between the input terminal of the current voltage converter and the output terminal of the inverting amplifier by the corresponding maximum voltage across the clipping means, that a second amplifier is inserted into the path from the input terminal of the current voltage converter to the inverting input terminal of the inverting amplifier, a third amplifier is provided, the input terminal of which is coupled to the output terminal of the second amplifier, and the output terminal of the third amplifier is coupled to the other end of the clipping means, that the product of the gains of the second and third amplifiers is approximately +1, but not greater than +1, and that the output voltage swing of the third amplifier is limited without saturation of the third amplifier.
- the second amplifier has a gain of about +1 as provided in an embodiment of the invention, the second amplifier does not affect the function of the inverting amplifier. If the gain is different from +1, it is necessary to change the gain of the inverting amplifier in order to get the same overall gain as discussed above.
- the clipping means can easily be realized by at least one diode providing a threshold voltage, preferably a Schottky diode having a barrier voltage or threshold of about 0.4 V in the flow direction.
- the mentioned limitation of the third amplifier can easily realized by a further clipping means (preferably at least one diode) connected between a fixed potential, e.g. ground, and that end of the clipping means which is not connected with the input terminal of the current voltage converter.
- a further clipping means preferably at least one diode
- transimpedance amplifiers for OTDRs transimpedance amplifiers for OTDRs
- the invention is also usable for other kinds of current voltage converters.
- the invention is usable for input signals having a high frequency as well as for low frequency input signals and for D.C. input signals.
- clipping or limitation of the input voltage Ui is shown only for one polarity. It is possible to provide clipping for two polarities by providing clipping means which also clip the other polarity. This can be realized easily by the use of Schottky diodes, since Schottky diodes are used in the flow direction and are blocked in the reverse direction (in contrast to for example Z-diodes which are used in the reverse direction). Also the below mentioned amplifiers U1, U2 and U3 have to be able to function for the two polarities of input signals.
- the transimpedance amplifier shown in Fig. 1 differs from known transimpedance amplifiers only in that it comprises a clipping means provided by a diode D2 having a parasitic capacitance represented by capacitor Cb, and in that the absolute value of the gain of the inventive amplifier is much smaller than that of the known amplifier.
- the inverting amplifier U1 has a great voltage gain of -v.
- the inverting amplifier U1 is supplied with supply voltages +Uv and -Uv. Between its output terminal C and the input terminal A of the transimpedance amplifier or current voltage converter a resistor RF performing a negative feedback is inserted.
- the photodiode Dph behaves approximately as a current source the current of which depends on the received light.
- Uo max is that maximum output voltage, at which the inverting amplifier is not yet saturated. This output voltage depends on the supply voltages +Uv and -Uv and its absolute value is necessarily smaller than the mentioned supply voltages.
- Uc is the threshold or barrier voltage of diode D2.
- the input voltage Ui is not held near zero as in known amplifiers, but can reach the barrier voltage or threshold voltage of the diode D2, which may be 0.4 V, and, therefore, this diode can function as a clipping means for the current voltage converter.
- Fig. 1 functions well for low frequencies since at low frequencies the capacitor Cb does not contribute remarkably to a reduction of the bandwidth of the current voltage converter.
- the lower end of diode D2 is not connected to ground as in Fig. 1.
- a second amplifier U2 is connected which has a positive gain V2+.
- the output terminal of the second amplifier U2 is connected to the input terminal of a third amplifier U3 having a positive gain V3+.
- the output terminal of the third amplifier is connected to the lower end of the diode D2.
- the gains of the second and third amplifiers U2 and U3, respectively, are chosen such that their product is at least approximately +1, but not greater than +1 in order to avoid instabilities.
- the gain of each amplifier U2 and U3 is +1.
- the voltage occurring at the terminal A appears also with the same value and phase at the point D, namely the output terminal of the third amplifier U3. Therefore, there is no voltage across the diode D2 and its associated capacitor Cb and any current cannot flow through the capacitor. This is valid as long as the voltage Ua at the point D follows exactly the voltage Ui at the terminal A.
- the third amplifier U3 is provided with a limitation of its output voltage without saturation of amplifier U3.
- this limitation is realized by a diode D3 connected between the output terminal of the third amplifier U3 and ground. Also diode D3 has a parasitic capacitance corresponding to the capacitor Ca. Therefore, the output terminal of the third amplifier U3 in Fig. 4 is also connected to the connecting point of the capacitors Cb and Ca.
- the voltage Ua at the input terminal A of the current voltage converter and therefore the voltage Ua at the point D is smaller than the threshold provided by the third amplifier U3 Fig. 3) or the diode D3 Fig. 4), the voltage Ua can vary corresponding to the voltage Ui.
- the threshold of the diode D2 is finally reached with the result that further increase of the current i i does not produce a further increase of the voltage Ui and, therefore, the output voltage Uo does not increase.
- the overall current voltage converter has a dynamic gain of zero. Nevertheless, none of the amplifiers U1, U2, U3 is saturated. Thus, as soon as the current i i becomes smaller such that the threshold of the diode D2 is no more reached, the current voltage converter immediately works correctly again.
- Fig. 5a to c shows the dependencies of Ua on i i , Ui on i i , and Uo on i i , respectively.
- Fig. 6 shows a realized circuit.
- the inverting amplifier U1 is realized in the embodiment by an integrated circuit CLC400.
- the non-inverting input of the inverting amplifier U1 is connected to ground.
- the amplifier U2 of Fig. 4 is realized by a field effect transistor (FET) Q1, the gate terminal of which is connected to the point A, the source terminal of which is connected to a point B and the drain of which is connected via a resistor R3 to a positive supply voltage.
- the point B is connected via a resistor R4 to the inverting input of the inverting amplifier U1.
- FET field effect transistor
- the inverting input of the inverting amplifier U1 is connected via a resistor R5 to the output of the inverting amplifier, and via an adjustable resistor R6 to a positive supply voltage. This makes it possible to compensate the D.C. offset between gate and source of Q1, such that for an input voltage Ui of 0 V the output voltage Uo is 0 V.
- the amplifier U3 of Fig. 3 is realized in Fig. 6 by an emitter follower comprising a NPN transistor Q2, the emitter of which is connected via a resistor R7 to a negative supply voltage and the collector of which is connected to a positive supply voltage.
- the emitter is connected to the connection point D between the two diodes D2 and D3.
- This circuit is very simple and automatically provides for a current limitation which is necessary in order to avoid the destruction of the diode D3 and/or the third amplifier U3.
- the base potential of Q2 is lowered because of the occurrence of an optical signal at the photodiode Dph, then the emitter voltage follows the base potential as long as the diode D3 is not conductive.
- this diode becomes conductive and prevents further lowering of the emitter potential of Q2.
- the base potential of Q2 is controlled more to negative values then the base emitter voltage of Q2 is reduced and thus the current through transistor Q2 is reduced, too. In this case the current through the diode D3 raises, however is limited by the resistor R7.
- the further advantage of this circuit is that the transistor Q2 never is switched off totally, since the emitter voltage of Q2 does never reach a potential lower than -Uc, and since the voltage Ui does never become more negative than -2xUc.
- the D.C. voltage offset Ugso between the gate and the source of the FET Q1 is adjusted by means of an adjustable constant current circuit (so-called current source) Iq such that the following equation is valid:
- U BEO With this setting, Ua is 0 V and the voltage drop across the diode D2 is also 0 V.
- the current source Iq may be realized in some cases by a resistor. However, the circuit shown in Fig. 7 may be used in all cases.
- a NPN transistor Q3 and an operational amplifier U4 are connected in the manner shown in Fig. 7.
- E is the output terminal of the constant current source or device and is to be connected with point B in Fig. 6.
- a bead at the collector of Q3 provides an inductor L1 preventing oscillations.
- R8 is a potentiometer for setting the output current.
- Q3 is of the type 2N3904 and U4 is of the type OP07.
- Fig. 6 the values of the different resistors, capacitors and so on are inserted.
- the value of for example "237" for R5 means 237 ohms.
- a value of for example 5.11 K means 5.11 kiloohms.
- the supply voltages of the circuit of Fig. 6 are, as inserted in the drawing, +5 V,-5 V, +12 V and -12 V.
- the photodiode Dph in the example has a metallic housing which is connected with the point B in order to reduce the influence of parasitic capacitances.
- the transistor Q1 is of the type MGF 1302
- transistor Q2 is of the type BFR 96
- the diodes D2, D3 are Schottky diodes of the type HP 2811 and the photodiode Dph has a responsivity of 15 A/W at about 1300 nm and is provided with a voltage -U D of about 80 V and thus much smaller than voltage Ui.
- the gain of the amplifier U1 is given by the resistors R5 and R4 and is about 2.34.
- the gains of the other amplifiers are +1 each.
- the maximum input voltage at the point A is -0.8 V
- the maximum output voltage at point C is 1.872 V.
- the Schottky diodes are connected in flow direction in order to use their threshold of 0.4 V in flow direction. Schottky diodes are very quick and have small parasitic capacitances. In other cases it might be advisable to use for example Z diodes (e.g. Zener diodes) and connect them in reverse direction as usual for those diodes.
- Z diodes e.g. Zener diodes
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP89123358A EP0433468B1 (de) | 1989-12-18 | 1989-12-18 | Strom-Spannungswandler |
DE68919704T DE68919704T2 (de) | 1989-12-18 | 1989-12-18 | Strom-Spannungswandler. |
US07/623,598 US5123732A (en) | 1989-12-18 | 1990-12-07 | Optical time domain reflectometer and current voltage converter for use therein |
JP2411567A JPH03261209A (ja) | 1989-12-18 | 1990-12-18 | 電流電圧変換器 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP89123358A EP0433468B1 (de) | 1989-12-18 | 1989-12-18 | Strom-Spannungswandler |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0433468A1 true EP0433468A1 (de) | 1991-06-26 |
EP0433468B1 EP0433468B1 (de) | 1994-11-30 |
Family
ID=8202243
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89123358A Expired - Lifetime EP0433468B1 (de) | 1989-12-18 | 1989-12-18 | Strom-Spannungswandler |
Country Status (4)
Country | Link |
---|---|
US (1) | US5123732A (de) |
EP (1) | EP0433468B1 (de) |
JP (1) | JPH03261209A (de) |
DE (1) | DE68919704T2 (de) |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5485264A (en) * | 1993-12-14 | 1996-01-16 | Antel Optronics, Inc. | High dynamic range OTDR data acquisition circuit |
US5465143A (en) * | 1994-01-27 | 1995-11-07 | Antel Optronics Inc. | ADP switch and adjustable data acquisition window |
US5504456A (en) * | 1994-02-09 | 1996-04-02 | Psc, Inc. | Low noise wide band amplifier |
US5410282A (en) * | 1994-03-14 | 1995-04-25 | Tektronix, Inc. | Wide dynamic range amplifier with error correction |
US5491548A (en) * | 1994-03-18 | 1996-02-13 | Tektronix, Inc. | Optical signal measurement instrument and wide dynamic range optical receiver for use therein |
US6356065B1 (en) * | 1999-08-30 | 2002-03-12 | Canon Kabushiki Kaisha | Current-voltage converter with changeable threshold based on peak inputted current |
US7671675B2 (en) * | 2007-08-20 | 2010-03-02 | Rohm Co., Ltd. | Output limiting circuit, class D power amplifier and audio equipment |
JP2010258982A (ja) * | 2009-04-28 | 2010-11-11 | Renesas Electronics Corp | 受光回路 |
CN102549946B (zh) * | 2011-12-12 | 2014-11-05 | 华为技术有限公司 | 光时域反射仪测试信号调制电路、无源光网络系统与装置 |
US10033413B2 (en) | 2016-05-19 | 2018-07-24 | Analog Devices Global | Mixed-mode digital predistortion |
US10224970B2 (en) | 2016-05-19 | 2019-03-05 | Analog Devices Global | Wideband digital predistortion |
US10466296B2 (en) | 2017-01-09 | 2019-11-05 | Analog Devices Global | Devices and methods for smart sensor application |
US10338224B2 (en) | 2017-03-27 | 2019-07-02 | Analog Devices Global Unlimited Company | High dynamic range analog front-end receiver for long range LIDAR |
US11018637B2 (en) | 2018-02-14 | 2021-05-25 | Analog Devices Global Unlimited Company | High dynamic range transimpedance amplifier |
US11555897B2 (en) | 2018-07-02 | 2023-01-17 | Analog Devices International Unlimited Company | Transimpedance amplifier with pulse widening |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3968361A (en) * | 1975-06-23 | 1976-07-06 | The United States Of America As Represented By The Secretary Of The Navy | Laser receiver anti-sun circuit |
US4578576A (en) * | 1983-03-30 | 1986-03-25 | Opto Systems, Inc. | Bar code reader with diode feedback in amplifier |
EP0185199A2 (de) * | 1984-11-13 | 1986-06-25 | Sumitomo Electric Industries Limited | Optischer Empfänger mit negativer Rückkopplung |
DE3543677A1 (de) * | 1985-12-11 | 1987-06-19 | Standard Elektrik Lorenz Ag | Vorverstaerker hoher dynamik und empfindlichkeit |
GB2194406A (en) * | 1986-07-18 | 1988-03-02 | Gen Electric Plc | Optical signal receiver circuits |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3440557A (en) * | 1965-09-14 | 1969-04-22 | Westinghouse Electric Corp | Amplifier apparatus with means to avoid saturation |
DE2748647C2 (de) * | 1977-10-29 | 1986-06-19 | Ernst Leitz Wetzlar Gmbh, 6330 Wetzlar | Verstärker für elektrische Signale |
US4960989A (en) * | 1989-03-28 | 1990-10-02 | Photon Kinetics Inc. | Optical time domain reflectometer having a receiver with selectively controlled gain |
US5023951A (en) * | 1989-04-14 | 1991-06-11 | Northern Telecom Limited | Optical receivers |
-
1989
- 1989-12-18 EP EP89123358A patent/EP0433468B1/de not_active Expired - Lifetime
- 1989-12-18 DE DE68919704T patent/DE68919704T2/de not_active Expired - Fee Related
-
1990
- 1990-12-07 US US07/623,598 patent/US5123732A/en not_active Expired - Fee Related
- 1990-12-18 JP JP2411567A patent/JPH03261209A/ja active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3968361A (en) * | 1975-06-23 | 1976-07-06 | The United States Of America As Represented By The Secretary Of The Navy | Laser receiver anti-sun circuit |
US4578576A (en) * | 1983-03-30 | 1986-03-25 | Opto Systems, Inc. | Bar code reader with diode feedback in amplifier |
EP0185199A2 (de) * | 1984-11-13 | 1986-06-25 | Sumitomo Electric Industries Limited | Optischer Empfänger mit negativer Rückkopplung |
DE3543677A1 (de) * | 1985-12-11 | 1987-06-19 | Standard Elektrik Lorenz Ag | Vorverstaerker hoher dynamik und empfindlichkeit |
GB2194406A (en) * | 1986-07-18 | 1988-03-02 | Gen Electric Plc | Optical signal receiver circuits |
Non-Patent Citations (2)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 11, no. 83 (E-489)(2530) 13 March 1987, & JP-A-61 237534 (FUJITSU LTD) 22 October 1986, * |
PATENT ABSTRACTS OF JAPAN vol. 3, no. 89 (E-126) 28 July 1979, & JP-A-54 66836 (FUJI SHASHIN KOKI K.K.) 29 May 1979, * |
Also Published As
Publication number | Publication date |
---|---|
DE68919704T2 (de) | 1995-06-01 |
US5123732A (en) | 1992-06-23 |
EP0433468B1 (de) | 1994-11-30 |
DE68919704D1 (de) | 1995-01-12 |
JPH03261209A (ja) | 1991-11-21 |
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